PROJECT SUMMARY: This proposal requests R13 support for the third meeting of the Gordon Research Conference (GRC) with an associated Gordon Research Seminar (GRS) for young scientists on ?Modulation of Neural Circuits and Behavior? from May 26-31, 2019, in Les Diablerets, Switzerland. Brains adjust information processing and optimize behaviors in response to ever-changing environmental demands. This astonishing flexibility relies on the modulation of brain functions at multiple levels, from synapses to neural circuits. The modulation of brain functions regulates basic biological states such as feeding, sleep or sex, and it is of key importance for cognitive brain functions such as attention and learning. Deep insights into neuromodulation are not only critical to understand the neural basis of intelligence and behavior but also to understand how different mental states, motivation, attention and other important phenomena are controlled. Moreover, mechanistic insights into neuromodulatory mechanisms are key to understand brain dysfunctions and diseases including depression, post-traumatic stress disorder, and many others. This conference will bring together scientists with diverse backgrounds to discuss current concepts and exciting new results in this broad field. The meeting will cut across disciplines and focus on topics that have a high potential to synergize. Rather than following traditional subdivisions of the broad field of neuromodulation, the session topics bridge between scientific communities and disciplines. We expect that the organized and informal discussions will generate new insights and highlight promising directions of future progress. This meeting is unique, since it brings together scientists from disparate fields to foster collaborative ideas and activities in the synthesis of the common principles of neuromodulation. This will be facilitated by specific sections of the program devoted to general discussions that will cover the presentations that address the common themes of each day. As a result of amazing advances in genomics and proteomics, computational analysis of complex datasets, new imaging and electrophysiology methods, and the ability to manipulate neural activity during innate and learned behavior, neuroscientists are now able to probe neuromodulation in identified neurons, circuits, and intact animals. The GRC/GRS on Neuromodulation will promote discussion of new research and strengthen communication between bench scientists, theorists, and tool developers. Finally, this meeting will feature participants of different generations, with representation of early pioneering investigators, current leaders, and junior investigators providing an exceptional opportunity for intimate exchanges of knowledge and ideas. Together these should drive promising future directions in the study of neuromodulation, which are in line with the mission of NINDS and its sister institutes, NIDA, NICHD, NIA and NIDCD.